The Experts below are selected from a list of 771 Experts worldwide ranked by ideXlab platform
Li Hui Lang - One of the best experts on this subject based on the ideXlab platform.
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A Novel Approach to Predict Wrinkling of Aluminum Alloy During Warm/Hot Sheet Hydroforming Based on an Improved Yoshida Buckling Test.
Materials (Basel Switzerland), 2020Co-Authors: Gaoshen Cai, Li Hui Lang, Dongxing Zhang, Jinlin Yang, Yongfeng Yuan, Sergei AlexandrovAbstract:In order to predict the wrinkling of Sheet metal under the influence of fluid pressure and temperature during warm/hot Hydroforming, a numerical simulation model for Sheet wrinkling prediction was established, taking into account through-thickness normal stress induced by fluid pressure. From simulations using linear and quadratic elements, respectively, it was found that the latter gave results that were much closer to experimental data. A novel experimental method based on an improved Yoshida Buckling Test (YBT) was proposed for testing the wrinkling properties of Sheets under the through-thickness normal stress. A wrinkling coefficient suitable for predicting wrinkling was also presented. Based on the numerical simulations, an experimental validation of wrinkling performance was conducted. Ridge-height curves measured along the main diagonal tensile direction of the Sheet were presented and showed that the wrinkling prediction criterion provided good discrimination. Furthermore, the wrinkling properties of several different materials were simulated to evaluate the accuracy of the prediction method, and the results revealed that the improved YBT gave good predictions for wrinkling in the conventional Sheet metal forming process, while the prediction results for wrinkling in warm/hot Sheet Hydroforming were also accurate with the fluid pressure of zero.
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a novel approach to predict wrinkling of aluminum alloy during warm hot Sheet Hydroforming based on an improved yoshida buckling test
Materials, 2020Co-Authors: Gaoshen Cai, Li Hui Lang, Dongxing Zhang, Jinlin Yang, Yongfeng Yuan, Sergei AlexandrovAbstract:In order to predict the wrinkling of Sheet metal under the influence of fluid pressure and temperature during warm/hot Hydroforming, a numerical simulation model for Sheet wrinkling prediction was established, taking into account through-thickness normal stress induced by fluid pressure. From simulations using linear and quadratic elements, respectively, it was found that the latter gave results that were much closer to experimental data. A novel experimental method based on an improved Yoshida Buckling Test (YBT) was proposed for testing the wrinkling properties of Sheets under the through-thickness normal stress. A wrinkling coefficient suitable for predicting wrinkling was also presented. Based on the numerical simulations, an experimental validation of wrinkling performance was conducted. Ridge-height curves measured along the main diagonal tensile direction of the Sheet were presented and showed that the wrinkling prediction criterion provided good discrimination. Furthermore, the wrinkling properties of several different materials were simulated to evaluate the accuracy of the prediction method, and the results revealed that the improved YBT gave good predictions for wrinkling in the conventional Sheet metal forming process, while the prediction results for wrinkling in warm/hot Sheet Hydroforming were also accurate with the fluid pressure of zero.
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investigation on the effect of pressure rate on formability of aluminum alloy during warm hot Sheet Hydroforming
AIP Advances, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing.Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing.
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research on al alloy Sheet forming formability during warm hot Sheet Hydroforming based on elliptical warm bulging test
AIP Advances, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:An elliptical warm/hot Sheet bulging test under different temperatures and pressure rates was carried out to predict Al-alloy Sheet forming limit during warm/hot Sheet Hydroforming. Using relevant formulas of ultimate strain to calculate and dispose experimental data, forming limit curves (FLCS) in tension–tension state of strain (TTSS) area are obtained. Combining with the basic experimental data obtained by uniaxial tensile test under the equivalent condition with bulging test, complete forming limit diagrams (FLDS) of Al-alloy are established. Using a quadratic polynomial curve fitting method, material constants of fitting function are calculated and a prediction model equation for Sheet metal forming limit is established, by which the corresponding forming limit curves in TTSS area can be obtained. The bulging test and fitting results indicated that the Sheet metal FLCS obtained were very accurate. Also, the model equation can be used to instruct warm/hot Sheet bulging test.
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Investigation on the effect of pressure rate on formability of aluminum alloy during warm/hot Sheet Hydroforming
AIP Publishing LLC, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing
Sergei Alexandrov - One of the best experts on this subject based on the ideXlab platform.
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A Novel Approach to Predict Wrinkling of Aluminum Alloy During Warm/Hot Sheet Hydroforming Based on an Improved Yoshida Buckling Test.
Materials (Basel Switzerland), 2020Co-Authors: Gaoshen Cai, Li Hui Lang, Dongxing Zhang, Jinlin Yang, Yongfeng Yuan, Sergei AlexandrovAbstract:In order to predict the wrinkling of Sheet metal under the influence of fluid pressure and temperature during warm/hot Hydroforming, a numerical simulation model for Sheet wrinkling prediction was established, taking into account through-thickness normal stress induced by fluid pressure. From simulations using linear and quadratic elements, respectively, it was found that the latter gave results that were much closer to experimental data. A novel experimental method based on an improved Yoshida Buckling Test (YBT) was proposed for testing the wrinkling properties of Sheets under the through-thickness normal stress. A wrinkling coefficient suitable for predicting wrinkling was also presented. Based on the numerical simulations, an experimental validation of wrinkling performance was conducted. Ridge-height curves measured along the main diagonal tensile direction of the Sheet were presented and showed that the wrinkling prediction criterion provided good discrimination. Furthermore, the wrinkling properties of several different materials were simulated to evaluate the accuracy of the prediction method, and the results revealed that the improved YBT gave good predictions for wrinkling in the conventional Sheet metal forming process, while the prediction results for wrinkling in warm/hot Sheet Hydroforming were also accurate with the fluid pressure of zero.
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a novel approach to predict wrinkling of aluminum alloy during warm hot Sheet Hydroforming based on an improved yoshida buckling test
Materials, 2020Co-Authors: Gaoshen Cai, Li Hui Lang, Dongxing Zhang, Jinlin Yang, Yongfeng Yuan, Sergei AlexandrovAbstract:In order to predict the wrinkling of Sheet metal under the influence of fluid pressure and temperature during warm/hot Hydroforming, a numerical simulation model for Sheet wrinkling prediction was established, taking into account through-thickness normal stress induced by fluid pressure. From simulations using linear and quadratic elements, respectively, it was found that the latter gave results that were much closer to experimental data. A novel experimental method based on an improved Yoshida Buckling Test (YBT) was proposed for testing the wrinkling properties of Sheets under the through-thickness normal stress. A wrinkling coefficient suitable for predicting wrinkling was also presented. Based on the numerical simulations, an experimental validation of wrinkling performance was conducted. Ridge-height curves measured along the main diagonal tensile direction of the Sheet were presented and showed that the wrinkling prediction criterion provided good discrimination. Furthermore, the wrinkling properties of several different materials were simulated to evaluate the accuracy of the prediction method, and the results revealed that the improved YBT gave good predictions for wrinkling in the conventional Sheet metal forming process, while the prediction results for wrinkling in warm/hot Sheet Hydroforming were also accurate with the fluid pressure of zero.
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investigation on the effect of pressure rate on formability of aluminum alloy during warm hot Sheet Hydroforming
AIP Advances, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing.Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing.
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research on al alloy Sheet forming formability during warm hot Sheet Hydroforming based on elliptical warm bulging test
AIP Advances, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:An elliptical warm/hot Sheet bulging test under different temperatures and pressure rates was carried out to predict Al-alloy Sheet forming limit during warm/hot Sheet Hydroforming. Using relevant formulas of ultimate strain to calculate and dispose experimental data, forming limit curves (FLCS) in tension–tension state of strain (TTSS) area are obtained. Combining with the basic experimental data obtained by uniaxial tensile test under the equivalent condition with bulging test, complete forming limit diagrams (FLDS) of Al-alloy are established. Using a quadratic polynomial curve fitting method, material constants of fitting function are calculated and a prediction model equation for Sheet metal forming limit is established, by which the corresponding forming limit curves in TTSS area can be obtained. The bulging test and fitting results indicated that the Sheet metal FLCS obtained were very accurate. Also, the model equation can be used to instruct warm/hot Sheet bulging test.
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Investigation on the effect of pressure rate on formability of aluminum alloy during warm/hot Sheet Hydroforming
AIP Publishing LLC, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing
Gaoshen Cai - One of the best experts on this subject based on the ideXlab platform.
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A Novel Approach to Predict Wrinkling of Aluminum Alloy During Warm/Hot Sheet Hydroforming Based on an Improved Yoshida Buckling Test.
Materials (Basel Switzerland), 2020Co-Authors: Gaoshen Cai, Li Hui Lang, Dongxing Zhang, Jinlin Yang, Yongfeng Yuan, Sergei AlexandrovAbstract:In order to predict the wrinkling of Sheet metal under the influence of fluid pressure and temperature during warm/hot Hydroforming, a numerical simulation model for Sheet wrinkling prediction was established, taking into account through-thickness normal stress induced by fluid pressure. From simulations using linear and quadratic elements, respectively, it was found that the latter gave results that were much closer to experimental data. A novel experimental method based on an improved Yoshida Buckling Test (YBT) was proposed for testing the wrinkling properties of Sheets under the through-thickness normal stress. A wrinkling coefficient suitable for predicting wrinkling was also presented. Based on the numerical simulations, an experimental validation of wrinkling performance was conducted. Ridge-height curves measured along the main diagonal tensile direction of the Sheet were presented and showed that the wrinkling prediction criterion provided good discrimination. Furthermore, the wrinkling properties of several different materials were simulated to evaluate the accuracy of the prediction method, and the results revealed that the improved YBT gave good predictions for wrinkling in the conventional Sheet metal forming process, while the prediction results for wrinkling in warm/hot Sheet Hydroforming were also accurate with the fluid pressure of zero.
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a novel approach to predict wrinkling of aluminum alloy during warm hot Sheet Hydroforming based on an improved yoshida buckling test
Materials, 2020Co-Authors: Gaoshen Cai, Li Hui Lang, Dongxing Zhang, Jinlin Yang, Yongfeng Yuan, Sergei AlexandrovAbstract:In order to predict the wrinkling of Sheet metal under the influence of fluid pressure and temperature during warm/hot Hydroforming, a numerical simulation model for Sheet wrinkling prediction was established, taking into account through-thickness normal stress induced by fluid pressure. From simulations using linear and quadratic elements, respectively, it was found that the latter gave results that were much closer to experimental data. A novel experimental method based on an improved Yoshida Buckling Test (YBT) was proposed for testing the wrinkling properties of Sheets under the through-thickness normal stress. A wrinkling coefficient suitable for predicting wrinkling was also presented. Based on the numerical simulations, an experimental validation of wrinkling performance was conducted. Ridge-height curves measured along the main diagonal tensile direction of the Sheet were presented and showed that the wrinkling prediction criterion provided good discrimination. Furthermore, the wrinkling properties of several different materials were simulated to evaluate the accuracy of the prediction method, and the results revealed that the improved YBT gave good predictions for wrinkling in the conventional Sheet metal forming process, while the prediction results for wrinkling in warm/hot Sheet Hydroforming were also accurate with the fluid pressure of zero.
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investigation on the effect of pressure rate on formability of aluminum alloy during warm hot Sheet Hydroforming
AIP Advances, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing.Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing.
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research on al alloy Sheet forming formability during warm hot Sheet Hydroforming based on elliptical warm bulging test
AIP Advances, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:An elliptical warm/hot Sheet bulging test under different temperatures and pressure rates was carried out to predict Al-alloy Sheet forming limit during warm/hot Sheet Hydroforming. Using relevant formulas of ultimate strain to calculate and dispose experimental data, forming limit curves (FLCS) in tension–tension state of strain (TTSS) area are obtained. Combining with the basic experimental data obtained by uniaxial tensile test under the equivalent condition with bulging test, complete forming limit diagrams (FLDS) of Al-alloy are established. Using a quadratic polynomial curve fitting method, material constants of fitting function are calculated and a prediction model equation for Sheet metal forming limit is established, by which the corresponding forming limit curves in TTSS area can be obtained. The bulging test and fitting results indicated that the Sheet metal FLCS obtained were very accurate. Also, the model equation can be used to instruct warm/hot Sheet bulging test.
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Investigation on the effect of pressure rate on formability of aluminum alloy during warm/hot Sheet Hydroforming
AIP Publishing LLC, 2018Co-Authors: Gaoshen Cai, Li Hui Lang, Zepu Gao, Sergei AlexandrovAbstract:Warm/hot Sheet bulging tests of 2A16-O aluminum alloy were conducted using elliptical bulging dies under various temperatures and pressure rates, in an effort to investigate the macroscopic and microscopic influence of the pressure rate on the formability and microstructural evolution of hydrobulging parts during warm/hot Sheet Hydroforming. The results revealed that the forming limit of the aluminum alloy was clearly influenced by the pressure rate as the temperature rose, wherein a lower pressure rate resulted in a higher forming limit. Metallographic observations and Energy Dispersive Spectrometer (EDS) analysis revealed no obvious influence of the pressure rate on the microstructure of hydrobulging parts after warm/hot Sheet Hydroforming. This study demonstrates that warm/hot Sheet Hydroforming of aluminum alloy may lead to an improved forming limit and inhibit microstructural degradation during processing
Karl Brian Nielsen - One of the best experts on this subject based on the ideXlab platform.
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The effect of the key process parameters in the innovative Hydroforming on the formed parts
Journal of Materials Processing Technology, 2007Co-Authors: Li Hui Lang, Joachim Danckert, Xianbin Zhou, Tao Li, Karl Brian NielsenAbstract:Abstract Due to the less of the knowledge about the Sheet Hydroforming, although the Sheet Hydroforming has gained more and more attentions in the world, it is quite difficult to be applied in the mass volume production. Based on the proposed innovative Sheet Hydroforming with uniform blank holding pressure, focused on the roundness, surface roughness, etc., using the materials of aluminum alloys, the key process parameters’ effect on the quality of the formed parts were investigated and the ways to improve the Sheet formability and the quality were discussed in both experiment and simulation and some good results have been obtained. It proves that the simulated results keep reasonable agreement with the experiment.
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optimized decision of the exact material modes in the simulation for the innovative Sheet Hydroforming method
Journal of Materials Processing Technology, 2006Co-Authors: Li Hui Lang, Joachim Danckert, Xianbin Zhou, Benny Endelt Kristensen, Karl Brian NielsenAbstract:Abstract Although Sheet Hydroforming has gained increasing interest in the world, it is difficult to determine the optimal forming parameters in FEM due to the incorrect application of material property parameters. In this paper, the properties of the material used in Sheet Hydroforming were obtained to meet the reality based on the identification of parameters for constitutive models by inverse modelling in which the friction coefficients were also considered. With consideration of identified simulation parameters by inverse modelling, some key process parameters including tool dimensions and pre-bulging on the forming processes in Sheet Hydroforming were investigated and optimized. The paper shows that the results from simulation based on the identified parameters were in good agreement with those from experiment.
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multi layer Sheet Hydroforming experimental and numerical investigation into the very thin layer in the middle
Journal of Materials Processing Technology, 2005Co-Authors: Li Hui Lang, Joachim Danckert, Karl Brian NielsenAbstract:Abstract Sheet Hydroforming has gained increasing interest in the automotive and aerospace industries because of its many advantages such as higher forming limitation, good quality of the formed parts and complicated parts can be formed, etc. The main advantage is that the uniform pressure can be transferred to everywhere at the same time. Based on the hydromechanical deep drawing (HDD) with uniform pressure onto the blank, the multi-Sheet Hydroforming with the very thin middle layer is investigated. Some features of the formed internal, external and middle layers including high drawing ratio, wall thickness distributions, free wrinkling and fracture, etc., are discussed in details. The process parameters’ effect on the forming process and the ways to improve the Sheets formability are discussed both for in experiment and simulation. The results from a simulation were in reasonable agreement with those from an experiment.
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research on the effect of the local constraints on Sheet Hydroforming with the movable die
NUMISHEET 2005: Proceedings of the 6th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Process, 2005Co-Authors: L X Zhou, Joachim Danckert, Shi H. Zhang, L H Lang, Karl Brian NielsenAbstract:An improved Sheet Hydro‐forming process was put forward, which was researched in the Institute of Metal Research (Chinese Academy of Sciences) and Aalborg University jointly. In this paper, the effects of local constraints on the Sheet deformation were researched experimentally. For this case, the local constraints include rigid tools (movable die) and surface roughness of the movable die, especially around the shoulder of the movable die. Finally, ASAME system and FEM are used to analyze the forming process to explain some results that were found in the experiment. In the simulation, the effects of the friction between the movable die and the blank and the movable die on the deformation of the blank are investigated in detail by using the FEM code LS‐DYNA. For the Sheet Hydroforming with local constraints, the contact between the Sheet and the dies affects the material flow and the fracture of the Sheet can be avoided. Moreover, the forming limit of Sheet metal can be remarkably improved. This process me...
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Hydroforming highlights Sheet Hydroforming and tube Hydroforming
Journal of Materials Processing Technology, 2004Co-Authors: Li Hui Lang, Joachim Danckert, D.c. Kang, S. J. Yuan, Z R Wang, Shi Hong Zhang, Karl Brian NielsenAbstract:Abstract At the present time, Hydroforming technology is used widely for forming lightweight or complicated components in the automotive industry and aerospace industry, etc. Recent developments and the character of Hydroforming, especially Sheet Hydroforming and tube Hydroforming, also known by the name of internal high pressure forming, are discussed in detail. Based on applications and by using liquid as a forming media, the state of the art and key technologies concerned with equipment, process control, simulation, etc. are explored in detail. Conclusions are drawn concerning possible future developments in Hydroforming technology.
S. J. Yuan - One of the best experts on this subject based on the ideXlab platform.
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mechanism analysis on thickness distribution of aluminum alloy hemispherical shells in double sided Sheet Hydroforming
The International Journal of Advanced Manufacturing Technology, 2017Co-Authors: Wenchao Liu, Yijin Chen, S. J. YuanAbstract:Thickness distribution is always an important criterion in evaluating the deformation uniformity of Sheet metal shells. In order to study the influence of double-sided liquid pressure on the thickness distribution of aluminum alloy curved shells, a dedicated experimental setup was designed to carry out double-sided Sheet Hydroforming processes. The thickness distribution of the formed shells were measured and compared under different loading paths. The deformation mode and the stress state were analyzed using simulation results to make a deeply understand on the mechanism of the thickness variation. It is shown that the forward pressure plays a slightly negative role in the thickness distribution of the formed parts. The deformation mode of the shells varies little when added forward pressures in the current experiments. The Von Mises stress and the effective strain of the components are improved when conducting the double-sided Hydroforming process. The larger thinning phenomenon when adding forward pressure on the blank is mainly caused by the increasing of reduced third principle stress. This paper can offer suggestions and guides to the future studies about the double-sided Sheet Hydroforming process.
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Analysis of wrinkling during Sheet Hydroforming of curved surface shell considering reverse bulging effect
International Journal of Mechanical Sciences, 2017Co-Authors: Y Z Chen, Yong Chao Xu, Weixiao Liu, Z. C. Zhang, S. J. YuanAbstract:Wrinkling in unsupported region is a worthy problem to be solved in Sheet metal forming process. Sheet Hydroforming is advantageous in the prevention of unsupported wrinkles. However, the simply increasing of liquid pressure is not enough to suppress the wrinkling even though with the occurrence of ???reverse bulging effect???.1 In order to predict and control the wrinkling quantitatively in unsupported region for thin-walled shells with curved surface, a theoretical model on critical wrinkling stress was proposed by considering proper ???reverse bulging effect??? based on energy method. The influence of liquid pressure and other parameters on the critical wrinkling stress was analyzed. The critical loading path of the liquid pressure to control wrinkling was obtained by combining critical wrinkling stresses and circumferential stresses. An experimental setup for an extremely thin-walled shell with semi-ellipsoidal geometry was designed and manufactured to verify the theoretical model. It is found that at a certain punch stroke, the magnitude of the critical wrinkling stress increases and that of circumferential compressive stress decreases with the improvement of the liquid pressure. The critical loading path can be utilized to get well formed shells with a ratio of thickness to diameter equals 0.27% in the experiments. The proposed method can be applied to predict and control wrinkling in unsupported region for Hydroforming of thin-walled shell with high accuracy and considerably reduced simulation time.
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Hydroforming highlights Sheet Hydroforming and tube Hydroforming
Journal of Materials Processing Technology, 2004Co-Authors: Li Hui Lang, Joachim Danckert, D.c. Kang, S. J. Yuan, Z R Wang, Shi Hong Zhang, Karl Brian NielsenAbstract:Abstract At the present time, Hydroforming technology is used widely for forming lightweight or complicated components in the automotive industry and aerospace industry, etc. Recent developments and the character of Hydroforming, especially Sheet Hydroforming and tube Hydroforming, also known by the name of internal high pressure forming, are discussed in detail. Based on applications and by using liquid as a forming media, the state of the art and key technologies concerned with equipment, process control, simulation, etc. are explored in detail. Conclusions are drawn concerning possible future developments in Hydroforming technology.